Edifier X600 speaker circuit burnt components identification

[mawais15]

Hi friends,
My edifier X600 speaker stopped working, only green led working, so I opened it up and found some components in bad shape (probably burned). I can solder and do basic stuff but I can't identify those components on my on . A little help to identify those components is what I'm looking for. Here is a close up snapshot of the pcb.

 

[dave9]

I almost didn't notice the link and thought attached pics were missing.

I don't see anything wrong, just some old darkened brown cement holding the capacitors down. There is one hairy looking spot to the top left of the capacitors but I can't tell if there is any problem there with that resistor and at the darkest spot right next to it, does it look like there should be a component there?

Generally you would measure for voltage at the capacitors to see if power is there, and measure for the audio signal along the signal path. You may have an opamp there, little DIP8 chip that is hard to read, I "think" I can almost make out "ST" and "4558" on it, so it might be an MC4558 opamp (datasheet: https://www.st.com/resource/en/datasheet/mc4558.pdf ).


Anyway you can get the datasheet for that to see the input and output pins to follow the AC low voltage audio signal with a multimeter and check for the power on its power pins and trace that further over to the power amp ICs. Looks like it has 3 x amp ICs on that heatsink, similarly you can get the datasheets for those to determine their pinouts.

Oh, you need an input audio signal playing to measure the audio signal through it.

I did see some pictures which suggest there is supposed to be a resistor in the darkest burnt looking area, see this page and resistor position R505, though it and R506 could have delaminated copper traces on the back of the PCB that need fixed before new resistors are put in.

Also see the following replacement board, if it is compatible it might be the quick cheap fix (well, quick for you but not on a calendar if it ships on the slow boat from China). It's probably also listed on an English language version of Aliexpress' site if you look long enough...

https://ru.aliexpress.com/item/2-1-...ier-circuit-board-ED-R201TXX/32823706110.html

 

[mawais15]

I almost didn't notice the link and thought attached pics were missing.

I don't see anything wrong, just some old darkened brown cement holding the capacitors down. There is one hairy looking spot to the top left of the capacitors but I can't tell if there is any problem there with that resistor and at the darkest spot right next to it, does it look like there should be a component there?

Generally you would measure for voltage at the capacitors to see if power is there, and measure for the audio signal along the signal path. You may have an opamp there, little DIP8 chip that is hard to read, I "think" I can almost make out "ST" and "4558" on it, so it might be an MC4558 opamp (datasheet: https://www.st.com/resource/en/datasheet/mc4558.pdf ).


Anyway you can get the datasheet for that to see the input and output pins to follow the AC low voltage audio signal with a multimeter and check for the power on its power pins and trace that further over to the power amp ICs. Looks like it has 3 x amp ICs on that heatsink, similarly you can get the datasheets for those to determine their pinouts.

Oh, you need an input audio signal playing to measure the audio signal through it.

I did see some pictures which suggest there is supposed to be a resistor in the darkest burnt looking area, see this page and resistor position R505, though it and R506 could have delaminated copper traces on the back of the PCB that need fixed before new resistors are put in.

Also see the following replacement board, if it is compatible it might be the quick cheap fix (well, quick for you but not on a calendar if it ships on the slow boat from China). It's probably also listed on an English language version of Aliexpress' site if you look long enough...

https://ru.aliexpress.com/item/2-1-...ier-circuit-board-ED-R201TXX/32823706110.html

Hi, sorry i do not understand much of it how the signal measuring and determining the faulty components works, like i said, i know how to solder and some other stuff since i am mechanical engineer by profession but i like to dig out things and fix stuff. That's why i posted here may be i could replace these burnt resistors and get it working. If that operational amplifier is totaled, i think i will get that aliexpress option.

 

[dave9]

The resistors are right next to what looks like the audio input jacks, if that is what they are for then it is strange they would suffer heat damage. If they are instead bleeder resistors for the capacitors, having them burn up should not effect the operation of the amp unless that caused a short circuit from mechanical damage to the bottom of the PCB or some random mishap of a resistor half flying off and shorting against a component next to it.

In my previous post I forgot to add the link to the page of pictures of your PCB, when I referred to resistor R505 I saw one on the picture 2/3rds of the way down this page:

http://old.edifier.com.ua/article.php?task=art&art=209

If they are for the audio signal you might have a matching set of resistors for the other channel to figure out the resistor values, and yet if they failed only on one channel, I'd think you would have noticed that the other channel still works (has output).